In a known method for driving a gas discharge lamp, e.g. an automotive xenon lamp, an alternating current is supplied to the gas discharge lamp. For example, a square wave current of a frequency of about 400 Hz is generated in a lamp driver circuit. The lamp driver circuit may comprise a direct current source and a commutation circuit for converting a direct current into an alternating current. Further, an ignition circuit may be provided for igniting the lamp. The ignition circuit may comprise a pulse transformer to supply a desired voltage pulse for igniting the lamp.
In a known system comprising a driver circuit, an ignition circuit and a gas discharge lamp, it was observed that relatively short interruptions in the current occurred substantially immediately after a reversal of a direction of the current, in particular immediately after the current to the lamp passing zero current.
In the known lamp driver circuit, after the current reversal, a voltage output by the lamp driver circuit is substantially equal to the operating voltage, i.e. the voltage over the lamp during stable operation. A difference between the operating voltage of the lamp driver circuit and an actual lamp voltage over the lamp is relatively small. Due to the relatively small voltage difference and the inductance of the ignition circuit between the driver circuit and the lamp, a current change, in particular after the current passing a zero current level, is slow. With a slowly changing, i.e. increasing, current, the current interruptions occur. Although normally the interruptions may not be visible to a person, in some cases the interruptions lead to a visible flickering of the lamp. The lamp may even extinguish.